Two cases of the Omicron coronavirus variant have been detected in the UK.
Here, the PA news agency looks at how the variant went from an emerging cause for concern in southern parts of Africa to arriving in the country.
UK scientists first become aware of the new strain after samples are uploaded on to a coronavirus variant tracking website from South Africa, Hong Kong and then Botswana.
Downing Street said the variant will be kept under “close investigation”.
Health Secretary Sajid Javid said early indicators show it may be more transmissible than the Delta variant and the vaccines may be less effective against it.
We have been made aware by @UKHSA of two UK cases of the Omicron variant. The two cases are linked and there is a connection with travel to southern Africa.
These individuals are self-isolating with their households while further testing and contact tracing is underway.
— Sajid Javid (@sajidjavid) November 27, 2021
It is announced that from the next day, six southern African countries – South Africa, Namibia, Lesotho, Eswatini, Zimbabwe and Botswana – will be added to the travel red list, meaning flights are suspended.
People arriving before then are told to self-isolate at home and take a PCR test on day two and day eight. Anyone who arrived up to 10 days prior are also told to take tests.
Mr Javid said scientists are “deeply concerned” about the variant, and mentioned turning to Plan B of coronavirus restrictions.
Scientists describe the variant as “very serious”, with Professor James Naismith, director of the Rosalind Franklin Institute, declaring it will “almost certainly” make the vaccines less effective.
Mr Javid updates MPs in the Commons on the variant called B.1.1.529, saying it “is highly likely that it has now spread to other countries”.
The Health Secretary tells of “very live” discussions over the prospect of adding further countries to the red list.
He confirms the Government is still following Plan A for managing Covid-19 in the autumn and winter but warns “if we need to go further, we will”.
Downing Street later urges those who have recently returned from one of the six southern African countries not to wait for NHS Test and Trace to contact them before getting tested.
On the back of the news, around £72 billion is wiped off London’s top shares as FTSE 100 drops by 3.6%, one of its biggest points fall since the early days of the pandemic in March 2020.
Later in the day, it is designated a variant of concern by the World Health Organisation, and named Omicron.
Boris Johnson speaks to South Africa’s president Cyril Ramaphosa to discuss the challenges of the variant.
Two cases of the Omicron Covid-19 variant are discovered in Brentwood and in Nottingham, the Department of Health & Social Care said.
The individuals that tested positive, and all members of their households, are retested and told to self-isolate.
Mr Javid said the two cases are linked, as Malawi, Mozambique, Zambia and Angola are added to the travel red list.
It is announced that the Prime Minister will host a press conference in Downing Street alongside chief medical officer Chris Whitty and chief scientific adviser Sir Patrick Vallance.
Mr Javid announced that new mask-wearing rules for shops and public transport would come into force the following week.
The Health Secretary said he expected imminent advice on broadening the booster programme from the Joint Committee on Vaccination and Immunisation.
He also said the testing regime for international arrivals would be introduced “as soon as possible”, with online passenger locator forms stating that PCR tests rather than lateral flow tests would be required from 4am the following Tuesday.
Scotland, Wales and Northern Ireland said they intended to mirror the border restrictions.